Automotive vehicle bodies usually have a gap between the back wall of the engine compartment and the lower edge of the windshield. This gap is bridged by a part that is referred to variously as a cowl, cowl panel, beauty panel or leaf screen. The cowl is secured along its lower edge to the body wall and along its upper edge to, or near, the lower edge of the windshield, and may be partially covered itself by the rear edge of the hood, especially in designs with hidden windshield wipers. Given its proximity to the windshield, the cowl provides a convenient foundation for the windshield wipers. Most often, the cowl is a single sheet structure to which is fixed a cylindrical housing that provides a sleeve bearing for the pivot shaft of a wiper arm. With such an arrangement, the pivot shaft must be passed through the bearing housing first, and the wiper arm completed afterward by attaching a crank arm to the lower end of the pivot shaft and a blade support to the upper end of the pivot shaft. Examples of such built up wiper arms and their pivot arrangements may be seen in USPN 4,509,878 to Bryson et al., and in USPN 4,028,950 to Osterday, both assigned to the assignee of the subject invention.
It is also known to use a wiper arm which, rather than being built up in stages, is integral or single piece. An integral arm has a crank arm on one end and a blade mount on the other offset from one another by an intermediate cylindrical journal that is generally perpendicular to both. A one piece arm cannot be passed through a sleeve or bearing housing. Instead, a stationary shaft that is fixed to a body support, and the journal arm is slipped over the free end of the shaft to pivot on the fixed shaft. An example may be seen in USPN 3,604,048 to Mainka. In all three of the above examples, the part that provides the bearing for the wiper arm, whether it be a cylindrical housing or a shaft fixed to the cowl, can act like a lever, tending to twist and bend the cowl when the arm is disturbed. Forces tending to disturb the arm may come from several sources, but the force of the drive linkage acting on the crank arm is generally the greatest. It may be difficult for a single sheet of material to resist these bending moments, especially when the pivot bearing has a significant length. This necessitates either that the cowl be made of heavy gage material, or that it be reinforced, as in Mainka.
USPN 3,264,670 to Barenyi et al shows, in one embodiment, a foundation for a wiper arm that consists of more than a single sheet. Specifically, as seen in FIG. 5, upper and lower metal panels are seamed together along their outer edges to create a box that is hinged along its lower edge only to the vehicle body, without being secured to the windshield at all. The wiper arm is the built up type, with a cylindrical bearing housing and a pivot shaft journal through it. The bearing housing is joined to the two spaced panels of the box in basically the same way that it would be joined to a single panel. That is, the bearing housing is passed through the panels, although two aligned holes are needed in this instance, as there are two panels. It would be just as difficult, more so in fact, to pass an integral type wiper arm through a pair of aligned holes, as opposed to passing it through a single hole in a single panel. It could be done if the holes were greatly oversized, but that would remove most of the panel material around the potential pivot point. Barenyi et al. is not directed to improving the mounting of the wiper arm to the cowl per se, but to mounting several other components, including the motor and drive linkage, to the cowl.